Corticotropin releasing factor (CRF) or hormone (CRH) is one of several neurohormones synthesized by specific hypothalamic nuclei in the brain where it activates the transcription of the pro-opiomelanocortin (POMC) gene resulting in release of adrenocorticotropic hormone (ACTH) and beta-endorphin from anterior pituitary cells (Vale et al, Science 213, 1394-1397 (1981)). The fundamental role of CRF is to prepare the organism for an appropriate response to various stressors such as physical trauma, insults of the immune system and social interactions. CRF also has CNS effects by acting at higher centers in the brain, particularly cortical regions where there is a widespread distribution of CRF neurons. CRF is believed to be a key intermediary in communication between the immune, central nervous, endocrine and cardiovascular systems (Sapolsky et al, Science 238, 522-524 (1987)). The role played by CRF in integrating the response of the immune system to physiological, psychological and immunological stressors has been described in the art, e.g. J. E. Blalock, Physiological Reviews 69, 1 (1989) and J. E. Morley, Life Sci. 41, 527 (1987).
CRF is a primary hormone controlling the hypothalamic-pituitary-adrenal axis. CRF exerts it pharmacological activity through at least two distinct G-protein coupled receptor subtypes which differ in their anatomical distribution and in their response to peptide ligands. Various splice modifications of these two subtypes have been observed (J. Saunders and J. P. Williams New Developments in the Study of Corticotropin Releasing Factor, Ann. Rep. Med. Chem. 2001 36:21-30). The first CRF receptor antagonists were peptides (see, e.g., Rivier et al., U.S. Pat. No. 4,605,642; Rivier et al., Science 1984 224:889). While these peptides established that CRF receptor antagonists can attenuate the pharmacological responses to CRF, peptide CRF receptor antagonists suffer from the usual drawbacks of peptide therapeutics including lack of stability and limited oral activity. More recently, small molecule CRF receptor antagonists have been reported (Saunders and Williams, supra; D. E. Grigoriadis et al., The CRF Receptor: Structure, Function and Potential for Therapeutic Intervention, Curr. Med. Chem.—Central Nervous System Agents 2001 1:63-97; D. A. Gutman et al Corticotropin-releasing factor antagonists as novel psychotherapeutics, Drugs of the Future 2000 25(9):923-31).
CRF antagonists are effective in the treatment of a wide range of stress-related illnesses, mood disorders such as depression, major depressive disorder, single episode depression, recurrent depression, child abuse induced depression, postpartum depression, dysthemia, bipolar disorder and cyclothymia; chronic fatigue syndrome; eating disorders such as obesity, anorexia and bulimia nervosa; generalized anxiety disorder; panic disorder; phobias; obsessive-compulsive disorder; post-traumatic stress disorder; pain perception such as fibromyalgia; headache; stress-induced gastrointestinal dysfunction such as irritable bowel syndrome (IBS), colonic hypersensitivity or spastic colon; hemorrhagic stress; ulcers; stress-induced psychotic episodes; inflammatory disorders such as rheumatoid arthritis and osteoarthritis; asthma; psoriasis; allergies; premature birth; hypertension; congestive heart failure; sleep disorders; neurodegenerative diseases such as Alzheimer's disease, senile dementia, Parkinson's disease and Huntington's disease; head or spinal cord trauma; ischemic neuronal damage; excitotoxic neuronal damage; epilepsy; stroke; psychosocial dwarfism; chemical dependencies and addictions; drug and alcohol withdrawal symptoms; stress-induced immune dysfunctions; immune suppression and stress-induced infections; cardiovascular or heart related diseases; fertility problems; and/or human immunodeficiency virus infections. Accordingly clinical data suggests that CRF receptor antagonists may represent novel antidepressants and/or anxiolytic drugs that may be useful in the treatment of the neuropsychiatric disorders manifesting hypersecretion of CRF.
While significant strides have been made toward achieving CRF regulation by administration of CRF receptor antagonists, there remains a need in the art for efficacious and selective small molecule CRF receptor antagonists. There is also a need for pharmaceutical compositions containing such CRF receptor antagonists, as well as methods relating to the use thereof to treat, for example, stress-related disorders. The present invention fulfills these needs, and provides other related advantages.
5,8-Dihydro-6H-pyrido[2,3-d]pyrimidin-7-ones have been reported with a variety of pharmacological activities. WO 200259083 (J. L. Adams et al.) discloses 5,8-dihydro-6H-pyrido[2,3-d]pyrimidin-7-one compounds which are p38 kinase. WO2001055148 (R. J. Booth et al.) and WO 98 33798 (D. H. Boschelli et al.) report related compounds with cyclin-dependent kinase inhibitory activity. WO 98 01428 (C. Dominguez et al.) disclose amidinoindoles, amidinoazoles and analogs as inhibitors of Factor Xa and of thrombin.